Thin Film Transistor Array Panel Alignment and Aperture Ratio
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Solution Overview
Problem
As liquid crystal displays increase in size, erroneous alignment of display panels during manufacturing can lead to deterioration of contrast ratio and mixed color phenomena, which is compensated by increasing the width of the black matrix, resulting in a decrease in aperture ratio.
Innovation Solution
A thin film transistor array panel design featuring a substrate with gate lines, data lines, thin film transistors, color filters, a common electrode, and passivation layers, where pixel electrodes have branch electrodes inclined at angles and a common signal line, along with a black matrix to prevent erroneous alignment and maintain aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the width of the black matrix is increased to compensate for erroneous alignment, then alignment tolerance is improved, but the aperture ratio of the pixels decreases
Solution Approach 1:
The patent introduces a new dimensional approach by forming color filters on upper parts of gate lines, data lines, and thin film transistors rather than only in pixel areas. This spatial redistribution allows the color filters to serve dual purposes: maintaining aperture ratio in pixel regions and providing alignment reference in non-pixel regions, thereby resolving the contradiction between alignment tolerance and aperture ratio without simply increasing black matrix width
Solution Approach 2:
The color filters are designed to perform multiple functions simultaneously: (1) providing color display in pixel regions, (2) serving as alignment reference marks for preventing erroneous alignment between display panels, and (3) maintaining aperture ratio by not extending into pixel areas. This multi-functionality allows the system to achieve both alignment tolerance and high aperture ratio without compromise
2Illumination intensity
If the aperture ratio is increased to improve transmittance, then light transmittance is improved, but alignment tolerance decreases
Solution Approach 1:
The patent utilizes the vertical dimension and non-pixel regions to place alignment reference color filters, separating the alignment function from the pixel aperture area. This allows pixel regions to maintain high aperture ratio for light transmittance while non-pixel regions provide alignment references for manufacturing tolerance
Solution Approach 2:
The color filters formed on gate lines, data lines, and thin film transistors serve as intermediary alignment reference marks. These reference marks mediate between the pixel structure and the alignment requirement, enabling precise alignment without compromising pixel aperture ratio or light transmittance
Data Source
AI summary
A liquid crystal display includes a first substrate, a plurality of gate lines formed on the first substrate, a plurality of data lines intersecting the gate lines, a plurality of thin film transistors connected to the gate lines and the data lines, a plurality of color filters formed on the gate lines, the data lines, and the thin film transistors, a plurality of first electrodes made of a transparent conductor formed on the color filters, and electrically connected to the thin film transistors, a first passivation layer formed on the first electrodes, a second electrode formed on the first passivation layer, and including a plurality of branch electrodes, a second substrate facing the first substrate, and a liquid crystal layer disposed between the first substrate and the second substrate.